A. Technical Field
The present invention pertains generally to digital image processing, and relates more particularly to image processing that allows for enhanced quality of images while achieving high compression ratios. The present invention may be incorporated into systems and methods.
B. Background of the Invention
With the proliferation of computer technology and devices capable of multimedia applications, storing, displaying, and transmitting images has likewise become quite prevalent. The ability to store, display, or transmit images is related to the file sizes of the images. Image files with smaller file sizes can be processed faster and can be more readily transmitted or stored than images with large files sizes.
Uncompressed digital documents typically have large file sizes. Digital files obtained from scanning documents can also have large file sizes, particularly if scanned at high resolution. To reduce the file sizes, a compression algorithm may be applied to the file.
Although compression methods help reduce file sizes, the compressed files are typically not without problems. Conventional image compression approaches that compress an entire image generally lead to unsatisfactory results in reconstructed image quality and compressed file size. When a high compression ratio is used, the compressed images may show disturbing artifacts, such as blurred text and blurred color boundaries. To obtain a high-quality compressed image, the compression ratio may need to be set very low, but the resulting file size will therefore not be substantially reduced. Thus, neither approach is particularly satisfactory.
Accordingly, what is needed are systems and methods that allow for high compression ratios of an image but that also maintain image quality.